From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marc Zyngier <marc.zyngier@arm.com>
Subject: Re: [PATCH v5 21/21] KVM: ARM64: Add a new kvm ARM PMU device
Date: Mon, 07 Dec 2015 15:06:20 +0000
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To: Shannon Zhao <shannon.zhao@linaro.org>, Shannon Zhao <zhaoshenglong@huawei.com>, kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org
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On 07/12/15 14:37, Shannon Zhao wrote:
> 
> 
> On 2015/12/7 21:56, Marc Zyngier wrote:
>>> +static int kvm_arm_pmu_set_attr(struct kvm_device *dev,
>>>> +				struct kvm_device_attr *attr)
>>>> +{
>>>> +	switch (attr->group) {
>>>> +	case KVM_DEV_ARM_PMU_GRP_IRQ: {
>>>> +		int __user *uaddr = (int __user *)(long)attr->addr;
>>>> +		int reg;
>>>> +
>>>> +		if (get_user(reg, uaddr))
>>>> +			return -EFAULT;
>>>> +
>>>> +		if (reg < VGIC_NR_SGIS || reg >= VGIC_NR_PRIVATE_IRQS)
>>>> +			return -EINVAL;
>>>> +
>>>> +		return kvm_arm_pmu_set_irq(dev->kvm, reg);
>> What prevents the IRQ to be changed while the VM is already running?
>> This should probably be a one-shot thing (change it once, be denied
>> other changes).
> 
> So add a helper like vgic_initialized to check whether vPMU is initialized?

Something like that, yes.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...